Model for injury to the foreleg of the Thoroughbred racehorse

A discussion is presented of contributing factors to the injury to the foreleg of the Thoroughbred racehorse. The critical part of the step is taken to be the first 10-20 ms after ground contact as the hoof slides forward and stops. Large nonaxial loads associated with the deceleration of the hoof are shown to arise. Results of accelerometer measurements on the hoof of a horse running at racing speed are presented as well as mechanical properties of the racing surface. The mechanical properties of the track surface, the type of shoe, and the degree of fatigue of the horse all work together to determine the level of risk.     

Absence of detectable human herpesvirus 8 in the semen of human immunodeficiency virus-infected men without Kaposi's sarcoma

The prevalence of human herpesvirus 8 (HHV-8)/Kaposi's sarcoma (KS)-associated herpesvirus was investigated in the semen of 99 human immunodeficiency virus (HIV)-infected men (median CD4 cell count, 357/mm3) by use of a polymerase chain reaction (PCR) assay capable of detecting <10 copies of HHV-8 DNA. Of the subjects, 95 (96%) self-identified as men who have sex with men (MSM), and 3 had a history of clinical KS. Seminal cell specimens were negative for HHV-8 in 98 subjects. None of the 26 without KS (27.1% of 96 tested) who were seropositive for HHV-8 by IFA for latency-associated nuclear antigens had HHV-8 detected in their semen. The only subject with any evidence for seminal HHV-8 DNA was seropositive for HHV-8 and had active KS. HHV-8 was detected in 10 (10.4%) of 96 peripheral blood mononuclear cell specimens. The prevalence of HHV-8 DNA by PCR in semen of HIV-infected MSM without KS is low.     

Effects of the glucocorticoid agonist, RU28362, and the antagonist RU486 on lung phosphatidylcholine and antioxidant enzyme development in the genetically obese Zucker rat

The biochemical maturation of the lung in late gestation and in the young animal is regulated by glucocorticoids. The present study was aimed at dissociating the different glucocorticoid receptor sites involved in these regulatory functions. The obese Zucker rat was selected as a model for this study as it exhibits hypersensitivity to glucocorticoid hormone action by virtue of its elevated receptor numbers and activity. Two synthetic steroid analogues were administered to obese animals; RU28362, a specific type II receptor agonist, and the type II antagonist RU486. RU28362 promoted a strong catabolic effect, which was associated with reduced food intake and the abolition of growth in the rats. The agonist, RU28362, attenuated developmental increases in antioxidant enzyme activities, and altered the growth of the tissue. At the age studied, development of the lung phosphatidylcholine (PC) system was almost complete, but RU28362 increased disaturated PC 16:0/16:0 concentrations by almost 2-fold, and altered the molecular composition of total pulmonary PC. RU486 attenuated the growth of the rats and reduced their food intake. Treatment with the type II antagonist attenuated lung growth and increased the activities of pulmonary copper zinc (Cu/Zn) and manganese (Mn) superoxide dismutases. RU486 had no effect on lung PC concentrations and molecular composition. The data suggest a role for type I glucocorticoid receptors in the regulation of the antioxidant enzyme system in the lung, as type II antagonism will channel endogenous glucocorticoid binding to the type I site. Type II receptor binding would appear to play a role in regulating the lung PC content.     

Resonance assignment of methionine methyl groups and chi 3 angular information from long-range proton-carbon and carbon-carbon J correlation in a calmodulin-peptide complex

Several simple 3D experiments are used to provide J correlations between methionine C epsilon methyl carbons and either the C gamma H2 protons or C beta and C gamma. The intensity of the J correlations provides information on the size of the three-bond J couplings and thereby on the chi 3 torsion angle. In addition, a simple 3D version of the HMBC experiment provides a sensitive link between the C epsilon H3 methyl protons and C gamma. The methods are demonstrated for a 20 kDa complex between calmodulin and a 26-residue peptide fragment of skeletal muscle myosin light chain kinase.     

STRL33, A novel chemokine receptor-like protein, functions as a fusion cofactor for both macrophage-tropic and T cell line-tropic HIV-1

The chemokine receptors CXCR4, CCR2B, CCR3, and CCR5 have recently been shown to serve along with CD4 as coreceptors for HIV-1. The tropisms of HIV-1 strains for subgroups of CD4(+) cells can be explained, at least partly, by the selective use of G protein-coupled receptors (GPCRs). We have identified a novel human gene, STRL33, located on chromosome 3 that encodes a GPCR with sequence similarity to chemokine receptors and to chemokine receptor-like orphan receptors. STRL33 is expressed in lymphoid tissues and activated T cells, and is induced in activated peripheral blood lymphocytes. When transfected into nonhuman NIH 3T3 cells expressing human CD4, the STRL33 cDNA rendered these cells competent to fuse with cells expressing HIV-1 envelope glycoproteins (Envs). Of greatest interest, STRL33, in contrast with CXCR4 or CCR5, was able to function as a cofactor for fusion mediated by Envs from both T cell line-tropic and macrophage-tropic HIV-1 strains. STRL33-transfected Jurkat cell lines also supported enhanced productive infection with HIV-1 compared with control Jurkat cells. Despite the sequence similarities between STRL33 and chemokine receptors, STRL33-transfected cell lines did not respond to any in a panel of chemokines. Based on the pattern of tissue expression of the STRL33 mRNA, and given the ability of STRL33 to function with Envs of differing tropisms, STRL33 may play a role in the establishment and/or progression of HIV-1 infection.